Apple's installaing Keynote 2 into the iWork sub-folder of applications may seem like an unnecessary annoyance to some, but it does have one potentially useful consequence: because the preferences and application support files for Keynote 2 will not overwrite those for the original version of Keynote, it is possible to switch between versions of Keynote -- or even run them both at the same time! Arguably this is of limited utility, although it might be helpful for those with either a lot of time invested in the original user interface. It might also be useful should any existing documents not open correctly in Keynote 2 -- not that I have encountered any such presentation files yet.

Specifically, both versions of Keynote will use any themes saved at /Library/Application Support/Keynote/Themes/; preferences for version 2 are written to ~/Library/Preferences/com.apple.iWork.Keynote.plist, while the original version's preferences are in com.apple.Keynote.plist.

It might not be a bad idea to keep Keynote 1 around for a while, until you're sure that all your programs are compatible. Omnioutliner Pro 3.0, for example, can't import Keynote 2 files yet, although it handles Keynote 1 files just fine.

I'm now regretting having deleted Keynote 1, since I use Keynote to get Powerpoint lectures into Omnioutliner. I may have to try to reinstall Keynote 1 just for this purpose.